The invention concerns a connecting element for the detachable connecting of two frame components, particularly of a support profile and of a frame profile, whereby the connecting element is positioned in a stationary manner in the frame profile which is constructed as a hollow profile and has, within a casing, at least one retaining element with which the connecting element, and thereby the frame profile as well, can be connected with the support profile in a detachable manner, and whereby an eccentric cam is positioned within the casing in a pivot-supported manner, which cam has at least one eccentric head, one eccentric cam disk and one support stud, by means of which the retaining element is conducted in a longitudinally movable manner in the casing, through which a component of the retaining element projecting out of the frontal side of the casing can be brought into contact with an undercut longitudinal groove of the support profile, and whereby the eccentric head of the eccentric cam which can be pressed into the casing against the force of a spring can be locked into a boring of the frame profile, as well as with a safety mechanism preventing the axial mobility of the eccentric cam into the insert position of the retaining element.
Such types of connecting elements are known in various forms of construction, and are used in particular for the connecting of support profiles and frame profiles, by means of which trade exhibition booths, among other types, are constructed. This connection should, on the one hand, be extremely solid, but, on the other hand, it should also be easy to produce and to detach again. For the easy installation and disassembly of a connecting element in a frame profile, the spring-loaded eccentric cam can be pressed, in the manner of a pushbutton, into the casing of the connecting element.
In order that this insertion not take place in an incorrect manner, and in particular not when the profile bars have been assembled, it has been proposed, in DE-C-31 53 232, to provide a stationary catch as a safety mechanism in the interior of the support casing, which, relative to the end part of the retaining element serving for the installation of the eccentric cam in the direction of insertion, is positioned in such a manner that the catch, in the discharge position of the retaining element is indeed positioned outside the end part, and thus permits its cross-swivelling capacity, but, in the insert position of the retaining element, it lies under the end piece, and blocks its cross-swivelling capacity.
Such a prevention of insertion has the disadvantage that the geometry of the casing must permit the application of a catch which is solid with the casing, whereby the retaining element must, to be sure, be inserted far enough into the casing and through the eccentric disk, on the one hand, that a secure connection of the frame profile with the support profile is ensured, but, on the other hand, however, the eccentric cam must be insertable if the retaining element is located in the discharge position. This has in practice as its consequence that the catch which is solidly attached to the casing is so dimensioned that it essentially only comes to lie below the retaining element in the end phase of the tightening process, and thereby blocks its cross-swivelling capacity.
It has, however, proven desirable that the eccentric cam be prevented from an unintended pressing inward, even during an early stage of the connecting process.
In EP-B-O 160 196, a connecting element has thus already been proposed, in which the eccentric disk is conducted, almost throughout the entire connecting process, into an aperture in a casing of the connecting element, so that the eccentric cam can not be pressed into the casing. Also, in such a type of prevention of inwardly pressing motion, the geometric relations of the connecting elements must permit the eccentric cam disk to be located in the aperture of the casing during the connecting process. Only if the retaining element is in its discharge position should it be able to be pressed inwardly. If the retaining element has been solidly tightened, the eccentric cam disk no longer need be located in the aperture of the casing, since the force-closure of the retaining element already prevents its insertion capacity itself.
It is thus the task of the present invention to create a connecting element of type already stated, in which a safety mechanism is provided which, in one defined range of the connecting process, prevents an unintended pressing in of the eccentric cam, but, however, within a likewise predetermined range, and particularly in the discharge position of the retaining element, permits the axial movability of the eccentric cam.